Block V - Cardiovascular

Question 1

Where is the bicuspid or mitral valve located?

Answer 1

The bicuspid valve is located between the left atrium and left ventricle

Question 2

What is an ECG?

Answer 2

An illustration of the cardiac conduction system

Question 3

What causes the P wave in an ECG pattern?

Answer 3

Depolarization of atrial muscle fibers

Question 4

In an ECG, during which wave does ventricular repolarization occur?

Answer 4

T wave

Question 5

Can ECG be used for determining a patient’s cardiac output stroke volume heart sounds end-diastolic volume?

Answer 5

No. Would be useful for determining heart rate.

Question 6

What is most responsible for the plateau of the cardiac action potential?

Answer 6

Both calcium and potassium channels

Question 7

Which cells have pacemaker potential?

Answer 7

The sino-atrial nodal cells

Question 8

What determines cardiac outpout?

Answer 8

Stroke volume multiplied by heart rate

Question 9

What is the ratio of stroke volume and end-diastolic volume?

Answer 9

Ejection fraction

Question 10

Are the stroke volume, stroke work, cardiac output, cardiac work the indices of ventricular performance?

Answer 10

Yes

Question 11

What is the most important factor in influencing the amount of blood pumped by the ventricle?

Answer 11

Venous return

Question 12

Which two great vessels bring deoxygenated blood back to the heart?

Answer 12

Superior and inferior vena cavae

Question 13

When does the first heart sound occur?

Answer 13

The first heart sound occurs during the phase of isovolumetric contraction

Question 14

What is the correct sequence for the path of cardiac impulse?

Answer 14

SA node, AV node, bundle of His, Purkinje fibers

Question 15

Where are the bundle of His and its branches located?

Answer 15

The bundle of His and its branches are located in the inter ventricular septum

Question 16

What are most responsible for phase 0 of a cardiac action potential?

Answer 16

Sodium channels

Question 17

What events cause cardiacmyocyte repolarization?

Answer 17

Calcium channels begin to close while more potassium channels open; potassium rapidly leaves the cell

Question 18

What relationship is defined by Frank-Starling’s law of the heart?

Answer 18

End-diastolic volume and stroke volume

Question 19

The opening of which channel in the auto rhythmic cell (pace maker cell) is responsible for the huge positive spike in membrane potential?

Answer 19

L-type calcium channel

Question 20

What is the typical stroke volume for an adult at rest?

Answer 20

70 or 80 mL

Question 21

Which two heart chambers pump oxygenated blood?

Answer 21

Left atrium and left ventricle

Question 22

When does the atrial systole occur

Answer 22

Towards the end of ventricular diastole

Question 23

Due to what event does the second heart sound occur?

Answer 23

Closing of the semilunar valves

Question 24

What is the heart rate dependent on?

Answer 24

Rate of pacemaker potential

Question 25

Which structure has the slowest conduction velocity of the cardiac impulse?

Answer 25

AV nodal fibers

Question 26

What is the correct sequence for the blood flow in the heart?

Answer 26

Right atrium, tricuspid valve, right ventricle, pulmonic valve, pulmonary circulation, left atria, mitral valve, left ventricle, aortic valve, aorta

Question 27

What is the result from delay of spread of electrical activation from atria to ventricles?

Answer 27

The delay allows atrial contraction to push an additional amount of blood into the ventricle before it contracts

Question 28

Which heart valves open during the diastole and systole of the heart cycle?

Answer 28

Diastolic: AV valves open and semilunar close. Systolic: AV close and semilunar open

Question 29

What changes in the ventricular pressure during isovolumic contraction phase of cardiac cycle?

Answer 29

The beginning of ventricular contraction causes leaflets of the mitral valve to close, continuation of ventricular muscle contraction will increase ventricular pressure very rapidly until it exceeds aortic pressure

Question 30

What is the Beta adrenergic effect on the ventricular myocyte's function?

Answer 30

It increase cAMP/PKA signal pathway which activates L-type calcium channels. Also, it causes release of free Ca from the SR. The general result is to increase muscle contractility

Question 31

What is the effect of activation of the baroreceptor reflex during hemorrhage?

Answer 31

Increase in HR due to activation of sympathetic tone on the vasculature

Question 32

If the systolic arterial pressure is 125 and the diastolic is 85, what is the estimated mean arterial pressure?

Answer 32

98 (diastolic + delta/3)

Question 33

What is the effect of nitric oxide on vascular smooth muscle cell function?

Answer 33

NO contributes to arteriolar vasodilation in the basal state

Question 34

What is active hyperemia?

Answer 34

Increasing blood flow of an organ when its metabolic activity increases

Question 35

Where does the slowest velocity of blood flow occur?

Answer 35

Capillaries

Question 36

What happens to the capillary hydrostatic pressure when arteriolar constriction occurs?

Answer 36

Decrease

Question 37

Where does the highest vascular resistance in the cardiovascular system occurs

Answer 37

Arterioles, where the large decrease in pressure within the systemic circulation takes places

Question 38

What is the effect on HR by decreasing parasympathetic stimulation?

Answer 38

HR increases

Question 39

What mechanism by which the exchange of lipid-soluble substances (CO2, O2) across the capillary membrane occur?

Answer 39

Diffusion

Question 40

How do you determine resistance to flow in a BV?

Answer 40

R increases in proportion to the length decreases with 4th power of the radius, increases with viscosity

Question 41

What will cause a decreases hematocrit in the microcirculation?

Answer 41

The parabolic velocity profile in arterioles and venues with velocity higher near the center of the vessel; deformable RBCs tend to be found closer to the center and away from arteriolar walls; plasma near the wall moves more slowly

Question 42

Is flow in microcirculation assumed to be steady

Answer 42

Yes

Question 43

Where is NO released from

Answer 43

Arteriolar endothelial cells

Question 44

What does the Starling's Law of Filtration predict?

Answer 44

- less filtration if tissue hydrostatic pressure increases - more filtration if plasma osmotic pressure decreases - less filtration if filtration coefficient decreases

Question 45

Is blood composed of approx. the same number of RBCs and WBCs?

Answer 45

No. RBC are 45% of blood volume while WBC are < 1%

Question 46

What types of cells are in the microvessel other than hematic cells?

Answer 46

ECs, pericytes, SMCs

Question 47

What is the myogenic and metabolic vasodilator hypotheses of auto regulation?

Answer 47

Myogenic autoregulation depends on stretch activated ion channels in vascular smooth muscle that, when stretched, allow Ca ions to enter and induce contraction. Metabolic autoregulation is thought to be due, in part, to substances produced in the tissue, in proportion to metabolism, which are vasoactive

Question 48

What is the Fahraeus effect?

Answer 48

More RBC in arterioles than capillaries

Question 49

What percent of blood is carried by capillaries?

Answer 49

At any given moment, 5% of circulating blood volume

Question 50

How close are cells from a capillary?

Answer 50

Most not more than 0.1mm

Question 51

What is the effect of venous constriction on the capillary hydrostatic pressure?

Answer 51

Increased

Question 52

What is the relationship between the arteriolar vasodilators production and the local oxygen level?

Answer 52

The production of vasodilators is inversely proportional to the local O2 levels

Question 53

Does EC produce more NO in response to shear stress?

Answer 53

Yes

Question 54

What is the effect of sympathetic stimulation on capillary hydrostatic pressure?

Answer 54

Decreased

Question 55

What factors determine changes in mean arterial pressure?

Answer 55

Cardiac output and/or total peripheral resistance

Question 56

Does parasympathetic stimulation control arteriolar resistance?

Answer 56

No or minimal

Question 57

How does a long-term regulation of BP by kidney occur?

Answer 57

It regulates blood volume by adjust salt and water excretion

Question 58

What is flow auto regulation?

Answer 58

Maintaining blood flow nearly constant in the face of pressure change

Question 59

What vascular region has the least smooth muscle?

Answer 59

Capillaries

Question 60

What is the most important factor for vascular resistance?

Answer 60

Diameter

Question 61

What are the nonadrenergic, noncholinergic autonomic neurons?

Answer 61

A 3rd subsystem of neurons that use NO as a neurotransmitter have been described and found to be integral in autonomic function, particularly in the gut and the lungs

Question 62

Where is the most blood in the cardiovascular system?

Answer 62

Veins

Question 63

How does the vasodilator production relate to local O2 level?

Answer 63

Inversely proportional to

Question 64

Are ECs involved in the myogenic response?

Answer 64

No